North Korea operates a rigorous system of eugenics that locks up those deemed subnormal, ranging from the disabled to dwarves, according to a UN report released yesterday.

A system of gulags is designed to ensure that those who do not conform to the state's designation of normal do not pass on their genes by having children.

"Those with disabilities are sent away from the capital city and particularly those with mental disability are detained in areas or camps known as 'Ward 49' with harsh and subhuman conditions," wrote Vitit Muntarbhorn, a Thai lawyer who is special rapporteur for human rights in North Korea. Evidence was gathered from defectors to South Korea.

The report said that dwarves are not allowed to reproduce and that they are rounded up and relocated. Marriages at the camps are permitted but having children is not.

Shut away for life, the afflicted are subjected to harsh and sub-human conditions. Food is scarce and of poor quality and beatings are commonplace. There are extensive reports of other forms of torture, including chemical weapons tests and germ agent experiments. Those not used as laboratory guinea pigs are ordered to carry out back breaking work.

North Korea is not the only totalitarian state to retain a fascination with a goal of breeding a better population by eliminating those with "weak" genes.

Since the fall of the Soviet bloc, it is one of the last states to implement the practice. Pyongyang is also dedicated to the principle of racial purity. Women who have sexual relations with the small Chinese community in North Korea are often purged.

The report said: "If they carry a child of non-Korean ethnicity, they may be subjected to discrimination and/or violence, with a dire impact on the babies."

The report was delivered to the UN General Assembly which has been asked to censure the Stalinist dictatorship.